Nozzle body for fuel injector

Abstract

A nozzle body for a fuel injector includes an outer air circuit, a fuel circuit, a dome air circuit, and a first prefilmer radially disposed between the outer air circuit and the dome air circuit. The first prefilmer is inclined to a central axis of the nozzle body by an inclination angle from 0 degree to 10 degrees, such that a fuel discharged by the fuel circuit at least partially impinges on the first prefilmer. An axial gap between a shroud throat of a shroud of the nozzle body and a trailing edge of the first prefilmer is between 1 mm and 2 mm, such that the fuel impinging on the first prefilmer is guided towards a dome air discharged by the dome air circuit.

I claim: 
     
         1 . A nozzle body for a fuel injector of a gas turbine engine, the nozzle body comprising:
 an inner air circuit extending along a central axis of the nozzle body and comprising an inner exit, wherein the inner air circuit is configured to discharge an inner air through the inner exit;   an outer air circuit radially outward of the inner air circuit with respect to the central axis and comprising an outer exit, wherein the outer air circuit is configured to discharge an outer air through the outer exit;   a fuel circuit radially disposed between the inner air circuit and the outer air circuit with respect to the central axis, the fuel circuit comprising a fuel exit that is located proximal to the inner exit, wherein the fuel circuit is configured to discharge a fuel through the fuel exit in a liquid state;   a dome air circuit radially outward of the outer air circuit with respect to the central axis and comprising a dome exit, wherein the dome exit is configured to discharge a dome air through the dome exit;   a first prefilmer radially disposed between the outer air circuit and the dome air circuit with respect to the central axis, the first prefilmer having a hollow frustoconical configuration, the first prefilmer comprising a radially inner surface facing the outer air circuit, a radially outer surface opposite to the radially inner surface and facing the dome air circuit, and a trailing edge extending between the radially inner surface and the radially outer surface and disposed at the outer exit, wherein the first prefilmer is configured to separate the dome air and the outer air, and wherein the first prefilmer is inclined to the central axis by an inclination angle from 0 degree to 10 degrees, such that the fuel discharged from the fuel exit at least partially impinges on the radially inner surface of the first prefilmer; and   a shroud disposed radially outward of the first prefilmer with respect to the central axis and at least partially defining the dome air circuit, the shroud comprising a shroud throat that defines a minimum diameter of the shroud with respect to the central axis;   wherein the shroud throat is disposed downstream of the trailing edge of the first prefilmer, and wherein an axial gap between the shroud throat and the trailing edge of the first prefilmer along the central axis is between 1 mm and 2 mm, such that the fuel impinging on the radially inner surface of the first prefilmer is at least partially guided towards the dome air.   
     
     
         2 . The nozzle body of  claim 1 , wherein the axial gap is 1.3 mm. 
     
     
         3 . The nozzle body of  claim 1 , wherein the inclination angle is 8.5 degrees. 
     
     
         4 . The nozzle body of  claim 1 , further comprising a second prefilmer at least partially defining the fuel circuit and forming a prefilmer lip disposed at the fuel exit, wherein the second prefilmer is disposed radially inward of the first prefilmer with respect to central axis, the second prefilmer comprising a radially outer cone surface facing the radially inner surface of the first prefilmer. 
     
     
         5 . The nozzle body of  claim 4 , wherein a first axial distance is defined between the prefilmer lip and the trailing edge of the first prefilmer along the central axis, wherein a second axial distance is defined between the prefilmer lip and the shroud throat along the central axis, and wherein the first axial distance is from 70% to 95% of the second axial distance. 
     
     
         6 . The nozzle body of  claim 1 , further comprising an inner air swirler disposed in the inner air circuit upstream of the inner exit. 
     
     
         7 . The nozzle body of  claim 1 , further comprising an outer air swirler disposed in the outer air circuit upstream of the outer exit. 
     
     
         8 . The nozzle body of  claim 1 , further comprising a dome air swirler disposed in the dome air circuit upstream of the dome exit. 
     
     
         9 . A fuel injector including the nozzle body of  claim 1 . 
     
     
         10 . A method for supplying a fuel to a gas turbine engine, the method comprising:
 providing a nozzle body for a fuel injector, the nozzle body comprising:
 an inner air circuit extending along a central axis of the nozzle body and comprising an inner exit; 
 an outer air circuit radially outward of the inner air circuit with respect to the central axis and comprising an outer exit; 
 a fuel circuit radially disposed between the inner air circuit and the outer air circuit with respect to the central axis, the fuel circuit comprising a fuel exit that is located proximal to the inner exit; 
 a dome air circuit radially outward of the outer air circuit with respect to the central axis and comprising a dome exit; 
 a first prefilmer radially disposed between the outer air circuit and the dome air circuit with respect to the central axis, the first prefilmer having a hollow frustoconical configuration, the first prefilmer comprising a radially inner surface facing the outer air circuit, a radially outer surface opposite to the radially inner surface and facing the dome air circuit, and a trailing edge extending between the radially inner surface and the radially outer surface and disposed at the outer exit, wherein the first prefilmer is inclined to the central axis by an inclination angle from 0 degree to 10 degrees; and 
 a shroud disposed radially outward of the first prefilmer with respect to the central axis and at least partially defining the dome air circuit, the shroud comprising a shroud throat that defines a minimum diameter of the shroud with respect to the central axis, wherein the shroud throat is disposed downstream of the trailing edge of the first prefilmer, and wherein an axial gap between the shroud throat and the trailing edge of the first prefilmer along the central axis is between 1 mm and 2 mm; 
   receiving an inner air within the inner air circuit and discharging the inner air through the inner exit;   receiving an outer air within the outer air circuit and discharging the outer air through the outer exit;   receiving a dome air within the dome air circuit and discharging the dome air through the dome exit;   receiving the fuel within the fuel circuit and discharging the fuel through the fuel exit in a liquid state;   at least partially impinging the fuel discharged through the fuel exit on the radially inner surface of the first prefilmer; and   at least partially guiding the fuel impinged on the radially inner surface of the first prefilmer towards the dome air exiting the dome exit.   
     
     
         11 . The method of  claim 10 , wherein the axial gap (G) is 1.3 mm. 
     
     
         12 . The method of  claim 10 , wherein the inclination angle is 8.5 degrees. 
     
     
         13 . The method of  claim 10 , wherein the nozzle body further comprises a second prefilmer at least partially defining the fuel circuit and forming a prefilmer lip disposed at the fuel exit, wherein the second prefilmer is disposed radially inward of the first prefilmer with respect to central axis, and wherein the second prefilmer comprises a radially outer cone surface facing the radially inner surface of the first prefilmer. 
     
     
         14 . The method of  claim 10 , wherein a first axial distance is defined between the prefilmer lip and the trailing edge of the first prefilmer along the central axis, wherein a second axial distance is defined between the prefilmer lip and the shroud throat along the central axis, and wherein the first axial distance is from 70% to 95% of the second axial distance. 
     
     
         15 . The method of  claim 10 , further comprising swirling, via an inner air swirler, the inner air prior to discharge from the inner exit. 
     
     
         16 . The method of  claim 10 , further comprising swirling, via an outer air swirler, the outer air prior to discharge from the outer exit. 
     
     
         17 . The method of  claim 10 , further comprising swirling, via a dome air swirler, the dome air prior to discharge from the dome exit.